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Overview

The CoW Protocol Python SDK supports multiple blockchain networks through the Chain enum. Each chain includes configuration for chain IDs, network names, and block explorer URLs.

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Accessing Chain Information

Import the Chain enum from the SDK: 
from cowdao_cowpy.common.chains import Chain

# Access chain properties
chain = Chain.MAINNET
print(chain.chain_id)      # SupportedChainId.MAINNET
print(chain.name)          # "ethereum"
print(chain.explorer)      # "https://etherscan.io"

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Supported Networks

Ethereum Mainnet

Chain ID: 1
Network Name: ethereum
Explorer: etherscan.io
Chain.MAINNET

Sepolia Testnet

Chain ID: 11155111
Network Name: sepolia
Explorer: sepolia.etherscan.io
Chain.SEPOLIA

Gnosis Chain

Chain ID: 100
Network Name: gnosis
Explorer: gnosisscan.io
Chain.GNOSIS

Arbitrum One

Chain ID: 42161
Network Name: arbitrum_one
Explorer: arbiscan.io
Chain.ARBITRUM_ONE

Base

Chain ID: 8453
Network Name: base
Explorer: basescan.org
Chain.BASE

Polygon

Chain ID: 137
Network Name: polygon
Explorer: polygonscan.com
Chain.POLYGON

Avalanche

Chain ID: 43114
Network Name: avalanche
Explorer: snowtrace.io
Chain.AVALANCHE

BNB Chain

Chain ID: 56
Network Name: bnb
Explorer: bscscan.com
Chain.BNB

Lens Network

Chain ID: 232
Network Name: lens
Explorer: explorer.lens.xyz
Chain.LENS

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Chain Properties

Each Chain enum value provides three key properties:
Returns the SupportedChainId enum value representing the numeric chain identifier.
from cowdao_cowpy.common.chains import Chain

chain = Chain.MAINNET
chain_id = chain.chain_id  # SupportedChainId.MAINNET (value: 1)
Returns the network name as a string, useful for display and configuration purposes.
from cowdao_cowpy.common.chains import Chain

chain = Chain.GNOSIS
network_name = chain.name  # "gnosis"
Returns the block explorer URL for viewing transactions and addresses on the network.
from cowdao_cowpy.common.chains import Chain

chain = Chain.ARBITRUM_ONE
explorer_url = chain.explorer  # "https://arbiscan.io"

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Usage Example

Here’s a complete example showing how to use chains when creating a swap: 
import os
import asyncio
from dotenv import load_dotenv
from web3 import Account, Web3
from web3.types import Wei
from cowdao_cowpy.cow.swap import swap_tokens
from cowdao_cowpy.common.chains import Chain

load_dotenv()
PRIVATE_KEY = os.getenv("PRIVATE_KEY")
ACCOUNT = Account.from_key(PRIVATE_KEY)

# Define tokens and amount
SELL_TOKEN = Web3.to_checksum_address("0xbe72E441BF55620febc26715db68d3494213D8Cb")
BUY_TOKEN = Web3.to_checksum_address("0xfFf9976782d46CC05630D1f6eBAb18b2324d6B14")
AMOUNT = Wei(5000000000000000000)

# Execute swap on Sepolia testnet
result = await swap_tokens(
    amount=AMOUNT,
    account=ACCOUNT,
    chain=Chain.SEPOLIA,  # Specify the chain
    sell_token=SELL_TOKEN,
    buy_token=BUY_TOKEN,
)

print(f"Order UID: {result.uid}")
print(f"Order URL: {result.url}")
When testing your integration, start with Chain.SEPOLIA to avoid risking real funds on mainnet.

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Getting All Supported Chains

You can retrieve all supported chains using the SUPPORTED_CHAINS constant: 
from cowdao_cowpy.common.chains import SUPPORTED_CHAINS

# Iterate through all supported chains
for chain in SUPPORTED_CHAINS:
    print(f"{chain.name}: Chain ID {chain.chain_id.value}")
The chain configuration is used internally by the SDK to determine API endpoints, contract addresses, and other network-specific settings.

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